Betray

Verb

1. To deliver into the hands of an enemy by treachery or fraud, in violation of trust; to give up treacherously or faithlessly.

   "An officer betrayed the city."

2. To prove faithless or treacherous to, as to a trust or one who trusts; to be false to; to deceive.

   "to betray a person or a cause"

3. To violate the confidence of, by disclosing a secret, or that which one is bound in honor not to make known.
4. To disclose (a secret, etc.) in deliberate violation of someone’s confidence.
5. To disclose or indicate, for example something which prudence would conceal; to reveal unintentionally.

   "Though he had lived in England for many years, a faint accent betrayed his Swedish origin."